Successful Aging: A Neuroscientist Explores the Power and Potential of Our Lives

by Daniel J. Levitin

They both recovered completely and have kept using their electronic calendars as a combination to-do list and sticky-paper reminder system. They love the freedom of being able to relax their minds, to let go of worrying about what they might be forgetting. They live more in the moment. And just the act of writing things down, of paying close attention to what they want to schedule, has improved their memories.

Individuals with dementia are often agitated, uncomfortable, angry, and confused. And for good reason—they don’t feel at home in their own bodies, their own surroundings. Part of compassionate care is giving them back a sense of self.

there appears to be no limit to the number of languages a very young child can learn. Studies have disproven the old folk wisdom that a multilingual child is only a fraction as good at each of the languages it speaks—the different languages coexist in the brain and don’t take away from one another.

Guinness World Records lists Ziad Fazah as being able to speak fifty-nine languages. (He himself claims to be fluent in “only” fifteen at a time and requires a practice period to get up to speed on the others he knows.) The seventeenth-century poet John Milton could speak English, Latin, French, German, Greek, Hebrew, Italian, Spanish, Aramaic, and Syriac.

Most of us will face a range of mental challenges as we age, and they come from multiple sources. Due to plaque buildup and partially blocked arteries (arteriosclerosis), blood flow may not be as smooth as it used to be. A reduction in the ability to produce neurochemicals may cause neurons to fire less efficiently.

Dopamine levels fall about 10 percent per decade, and serotonin- and brain-derived neurotrophic factor levels also fall off with increasing age.

Years of alcohol consumption can lead to neuronal death and are implicat...

most adults experience a gradual reduction in brain volume after the age of thirty-five of about 5 percent per decade through age sixty, with the decline speeding up after age seventy. All of these factors lead to a general slowing of cognitive function. Much of this volume and weight reduction comes from shrinkage of the prefrontal cortex and hippocampus. The prefrontal cortex is what we use to set goals, make plans, divide a large project up into smaller pieces, exercise impulse control, and decide what we’re going to pay attention

The prefrontal cortex is also the first cortical region to show wear and tear as we get older. “That is why one of the most significant problems in older adults is the ability to keep track of thoughts and prevent stray ones from interfering,”

“Brain fitness as we age depends significantly on maintaining a healthy and active prefrontal cortex. The more we engage this brain region during daily activities, the better we will be able to control our thoughts and think flexibly.”

One of the most important things we can do to promote neural health involves myelin, which is 80 percent lipids. Our bodies’ ability to create and maintain myelin relies on dietary fats. Without them, or with a reduced ability to metabolize them, we see even more decay of the myelin sheath than is caused by aging alone.

Two easy mechanisms are eating fatty fish and getting enough vitamin B12. You may have heard the expression that fish is brain food, and that’s true. Fish oil provides the omega-3 fatty acids that the body uses to create myelin, and it can even repair damaged myelin caused by traumatic brain injury.

The cumulative effects of aging include everything from repeated exposure to toxins, illness, and the breakdown of DNA. There are a number of things that can damage DNA—tobacco smoke, ultraviolet rays from suntanning or tanning booths, certain drugs, and even stress.

We experience different modes of attention throughout the day. Two of the most noticeable are what neuroscientists call the central executive mode and the default, or resting-state mode. In the central executive mode we are focused, we direct our thoughts and filter our distractions. In the resting-state mode, our thoughts meander, they are loosely connected, and this has led to its being called the “daydreaming mode” of the brain. The daydreaming mode is restorative after you’ve been focusing on something intensely for a while, and it is often the mode during which you can effectively solve problems.

If you’ve ever been walking down the breakfast cereal aisle in the grocery store, not thinking about anything in particular, and the solution to a problem you’ve been struggling with suddenly appears in your head, that’s the daydreaming mode. The two modes tend to work in opposition, like a seesaw—when one is up, the other is down.

Alzheimer’s is characterized by abnormal protein aggregates (plaques) and neurofibrillary tangles, which disrupt neural transmission. One particular protein, called beta-amyloid, starts out by destroying synapses before it clumps into plaques that cause neuronal death. The disease typically starts in the medial temporal lobe and then spreads throughout much of the brain.

Some early evidence suggests that chronic inflammatory processes feed existing Alzheimer’s disease, or perhaps even cause it. Some researchers have suggested that taking NSAIDs (nonsteroidal anti-inflammatory drugs) as much as ten years before the expected onset of Alzheimer’s symptoms might be advisable, but a great deal of further work needs to be done—we don’t know what other negative effects may accrue from such chronic use of NSAIDs.

The APOE gene is a genetic factor that greatly increases the risk of developing dementia, as well as late-onset Alzheimer’s disease (after the age of sixty-five). The problem with such information is that genetic contributions to dementia are complex; interactions with other genes and other biomarkers need to be taken into account in order to get an accurate picture. APOE alone does not cause dementia or Alzheimer’s. And, of course, an increased risk does not mean you’ll develop the disease with perfect certainty, and in some groups, the presence of the gene is protective.

Stroke A stroke is the restriction of blood flow in the brain that causes cell death.

The main risk factor for any type of stroke is high blood pressure.

Lifestyle interventions, such as restricting salt intake, learning to cope with stress, and aerobic exercise also lower blood pressure. For years, doctors advised people over fifty or sixty to take a baby aspirin (around 80 mg) every day as a preventative, to thin the blood, thus reducing the risk of a blood clot or ischemic stroke. The problem with this is that if you have a hemorrhagic stroke, the thin blood won’t clot and the damage from internal bleeding will be more severe. It’s one of those weird situations in medicine where you effectively have to choose how you want to die or be otherwise damaged: Would I rather have the damage from a clot or from a rupture?

On the other hand, if you’ve already experienced an ischemic stroke—and you know for sure that it was ischemic and not hemorrhagic—taking aspirin or other blood thinners is usually advised to reduce the chance of a second ischemic stroke. As of 2019, there is mounting evidence that taking the low dose aspirin is preventively not worth the risk, and a study of twelve thousand Europeans found that it had no effect on stroke.

The aftermath of stroke is highly variable. Some people experience no aftereffects at all; others are left partially paralyzed, are unable to speak, o...

Neuroplasticity does not seem to slow down nearly as much for older adults who have been making demands on their brains to think differently and rewire for many years. If you’re involved in the creative arts—painting, sculpture, architecture, dance, writing, music, and other forms of creativity—you’ve been exercising your brain, pushing your brain, in interesting ways all along because every project you undertake requires new adaptations, some way of looking at the world differently, and then acting on it. And it’s not limited to the creative arts—any job or hobby that requires you to interact with the world and to respond to it differently each time is an activity that helps protect the brain against dementia, rigidity, and neural atrophy. This can apply to housepainters, arborists, athletes, serial entrepreneurs, publicists, professional drivers, crossword puzzle players, bridge players, and so on.

You’ve probably experienced this yourself in daily activities and not even known that it was something as lofty as neuroplasticity or brain adaptation: driving a rental car, using a pen with a body of a different thickness than you’ve used before, cooking in someone else’s kitchen, buttoning up a new shirt, listening to someone speak in an accent you’ve never heard before. Even something as simple as drinking coffee out of a new cup that is weighted differently and has a differently sized handle than you’re used to. These are all examples of adaptive neuroplasticity.

Neuroplasticity continues until we die, but, like reaction times, it does slow down, and the extent to which brain remodeling can occur is reduced as we age. The good news is that previously learned motor skills are well-preserved at least through age sixty and for many well beyond their eighties.

One of the most protective things you can do against aging is to learn a manual skill when you’re young and keep it up. The next best thing you can do is to start learning something new when you’re old. The efficiency with which we learn new motor skills, however, declines with age—we can learn well into our nineties and beyond, but the learning takes more concentration and more time.

If you are thinking that there might be a correlation between this and the tendency for older adults to become more politically conservative—to want things to stay the way they are—you might be on to something.

Fortunately, neuroplasticity offers the brain a number of ways to compensate for the decline in the quality of sensory information. Neuroplasticity leverages what our bodies can tell us about the world, how and how well our senses perceive it. Understanding how perception works and develops is essential to understanding successful aging.

Sir Isaac Newton, a contemporary of Locke’s, knew that the rich perceptual experiences we have are created in our brains, not out there in the world. He wrote that the light waves illuminating a blue sky are not themselves blue—they only appear blue because our retina and cortex interpret light of a particular frequency, 650 terahertz, as blue. Blueness is an interpretation that we place on the world, not something that is objectively there.

Vision Perhaps the most well-known and reliable marker of aging is declining vision, specifically, an inability to read. Starting around age forty, people begin showing up at the reading glasses section of the nearby drugstore or make appointments with an optometrist.

This change in vision is called presbyopia. It occurs because of age-related changes in proteins in the lens, making the lens harder and less elastic over time. Age-related changes also take place in the muscle fibers surrounding the lens. With less elasticity, the eye has a harder time focusing up close, which takes more muscle tension than focusing far away.

There is an emerging but still small body of evidence linking cataracts to smoking and diabetes. Healthy practices going back to your teen years can influence this outcome years later. The best cataract protection comes from wearing sunglasses when you’re outdoors starting at a young age. Cataract surgery replaces your cloudy, protein-clumpy lens with an artificial lens. It is one of the most common and safest operations performed if it is done by a qualified doctor at a good facility. Starting at age sixty, you should have your eyes examined every two years for early detection of cataracts, macular degeneration, glaucoma, and other diseases of the eye. Early detection of these can save your ability to see.

Hearing Perhaps the next most common failing is hearing—presbycusis—and most of us will end up needing hearing aids at some point. Presbyopia and presbycusis come from the Greek root presby, which means old.

Like the ultraviolet rays of the sun damaging the lens of the eye, environmental factors can damage the ear: Noise-induced hearing loss, from prolonged exposure to sudden loud sounds in the workplace or at rock concerts, can damage the hair cells of the ear irreversibly. The best preventative is to wear earplugs when you’re going to be around loud noises. High blood pressure, diabetes, and chemotherapy can also irreparably damage the hair cells.

Foods that are high in antioxidants, such as blueberries, might be a promising way to forestall or correct this, but it’s too early to tell; evidence for the effectiveness of antioxidant foods is mixed. Still, the Mayo Clinic and other experts recommend making them a regular part of your diet while the evidence comes in, not just for fending off hearing loss, but for a range of maladies including cancer and Alzheimer’s (more on that later).

Hearing loss affects one-third of people in the United States between the ages of sixty-five and seventy-four, and (as I mentioned earlier) nearly half of people over seventy-five.

Touch Our sense of touch also declines with age. Decreased blood flow to the extremities—hands and feet—can impair the touch receptors there; older adults may not be able to feel that the shower is slippery or be able to differentiate between hot and cold water.

It’s tempting to think of taste only for the pleasure it brings—a good meal, a fine wine, your favorite dessert, your loved one’s skin. But taste is an important sense for other reasons. Taste deficits alter food choices and lead to poor nutrition, weight loss, and reductions in immune-system function when we don’t ingest the vitamins and minerals we need. In addition, taste helps us prepare the body to digest food by triggering the production of saliva, alongside gastric, pancreatic, and intestinal fluids. The pleasurable feelings from eating tasty food become more important in old age when other sources of sensory gratification—like physical contact—may have become compromised or are less frequent.

Many older adults complain that food lacks flavor. This is usually due to olfactory deficits—smell works in tandem with taste to convey the flavor of food and drink, and sensors inside the cheeks feed into the brain’s olfactory centers.

I had given up my morning breakfast of tasty granola, bacon, and omelets for oatmeal and egg whites—in short, I was eating a bland diet, not by design, but as a by-product of trying to eat healthy. The fix? When I got home, I started putting Cholula and Tabasco sauce on my egg whites, and spicing up my morning oatmeal with cinnamon and nutmeg, and my zest for food came back without my gaining any weight or increasing my cholesterol numbers.

we’ve got to get ourselves back to the garden.” Plants, dirt, sky, and wildlife offer stimulation to our perceptual systems. Perhaps the visual input is the first thing you think of, but there are sounds and smells as well; the taste of wet air before a rain; the touch of tree bark or rocks underneath our feet.

Neurologist Scott Grafton is a big believer in the healing power of the outdoors. “Take old people out of a complex environment and they age quicker,” he notes. “The brain doesn’t just need physical activity to remain vital, but complex physical activity—the brain needs it to stay healthy and engaged.” Something as simple as walking in a new environment provides this critical brain input. Your feet have to adjust to different surfaces and angles, your ankles need to move in conjunction with your feet.

Many older adults have an urge to travel, and this may originate in an adaptive, biological drive that will serve to keep them healthy for longer, especially if the travel involves walking tours of new places.

Neuroplasticity is what keeps us young, and it is only a walk in the park away.

The most noticeable effect of aging, apart from wrinkles and hair loss, is the decline in intellectual processing that some people undergo. But not all people. Some of us remain happy, healthy, and mentally fit while others start to lose it. What’s going on in the brains of those older adults who remain mentally vital into their eighties and nineties? Are they just barely hanging on to what they had, or are they actually improving in some ways? I’ve come to believe that life after seventy-five can launch a period of intellectual growth, and not mere maintenance.

The Healthy practices of the COACH principle are partly responsible for people with increased health spans: Curiosity, Openness, Associations, Conscientiousness, and Healthy practices. The people I’ve encountered who are still contributing to society, to arts and science, to their communities, and to their families are doing all five of these. Some examples of Healthy practices: My mother has been a vegetarian for thirty-five years. George Shultz has a Pilates instructor and works out regularly. Conscientiousness helps us to follow through on the things we start, to actually get a Pilates trainer and to show up. Openness to experience allowed my mother to immerse herself in the world of theater at age seventy-eight, and George Shultz to go against decades of Republican Party platform about climate change and recreational drug use. How about Associations? My mother and George Shultz both reached out to, and engaged with, others to help them achieve their visions. Their collaborations are sometimes maddening and frustrating, but they are also mentally challenging and, ultimately, fulfilling. Curiosity fueled the intellectual desire to do all these new things.

Many people we regard as brilliant often did poorly in school for a variety of other reasons, and their IQ scores, as established by standardized tests, might have been in the “normal” rather than “gifted” range. But you couldn’t say they lacked intelligence. So something is clearly wrong with the idea that intelligence is one thing that can be measured by a single number, IQ.

At the other end of the continuum, we now know that students who do well in school often have advantages that other students lack, such as parents or older siblings who value education, who help them with their homework and teach them ahead of time what they’ll encounter in class. That is, school becomes a place where privileged students can show off what they already learned at home. Does that mean they have more intelligence? Or does it mean they’ve been exposed to more knowledge? Those may not be the same thing at all.

“school failure may be partly explained by the mismatch between what students have learned in their home cultures and what is required of them in school.”